Layered and poriferous (Al,C)-Ta2O5 mesocrystals supported CdS quantum dots for high-efficiency photodegradation of organic contaminants

Preparation of high-performance composites photocatalysts for organic pollutants degradation is of great significance. In this work, elemental doping was employed to realize the visible-light harvesting and visible-light photocatalysis of the (Al,C)-Ta2O5 mesocrystals following by introduction of CdS quantum dots (QDs) into layered and poriferous (Al,C)-Ta2O5 nanosheets for fabrication of S-scheme charge transfer pathways. In this work, the higher temperatures treatment induced the successful transformation of (Al,C)-Ta2O5 nanosheets from Ta3AlC4 MAX. The experimental results also revealed that CdS QDs/(Al,C)-Ta2O5 composites showed highly enhanced visible-light absorption and visible-light photocatalytic tetracycline degradation performance. The optimal photocatalytic reaction rate constant of the CdS QDs/(Al,C)-Ta2O5-30% composite reached as high as 0.1117 min(-1), which was approximately 27.24 times of the (Al,C)-Ta2O5 nanosheets and 2.43 times of CdS QDs, far better than those of commercial Ta2O5 and pristine Ta3AlC4. Meanwhile, the prepared CdS QDs/(Al,C)-Ta2O5 composites were also employed for efficient photodegradation of norfloxacin. Besides, the effects of various experimental parameters, reactive species determination, and band structures were also investigated. The improved visible-light photocatalytic performance of the CdS QDs/(Al,C)-Ta2O5 composites was mainly attributed to fabrication of S-scheme charge transfer pathways for efficient charge separation.

Automated summary

Preparation of high-performance composites photocatalysts for organic pollutants degradation is of great significance. Elemental doping and introduction of CdS quantum dots were employed to enhance the visible-light photocatalytic performance of (Al,C)-Ta2O5 nanosheets. The CdS QDs/(Al,C)-Ta2O5 composites showed highly enhanced visible-light absorption and photocatalytic degradation performance compared to Ta2O5 and Ta3AlC4. The enhanced performance was attributed to the fabrication of efficient charge separation pathways.